Cancer Staging References

The AJCC has developed and compiled cancer staging references for quickly finding important information about different types of cancers. These references and tools are excellent resources for medical professionals treating patients with cancer.

Learn More About Cancer Staging

What is Cancer Staging?

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Cancer staging is the process of determining how much cancer is in the body and where it is located. Staging describes the severity of an individual's cancer based on the magnitude of the original (primary) tumor as well as on the extent cancer has spread in the body. Understanding the stage of the cancer helps doctors to develop a prognosis and design a treatment plan for individual patients.

Staging provides a common language for doctors to effectively communicate about a patient’s cancer and collaborate on the best courses of treatment.

Understanding the cancer’s stage is also critical to identifying clinical trials that may be appropriate for particular patients.

What are the Different Types of Staging?

There are four different types of staging:

Clinical Staging determines how much cancer there is based on the physical examination, imaging tests, and biopsies of affected areas.

Pathologic Staging can only be determined from individual patients who have had surgery to remove a tumor or explore the extent of the cancer. Pathologic staging combines the results of both the clinical staging (physical exam, imaging test) with surgical results.

Post-Therapy or Post-Neoadjuvant Therapy Staging determines how much cancer remains after a patient is first treated with systemic (chemotherapy or hormone therapy) and/or radiation therapy prior to their surgery or where no surgery is performed. This can be assessed by clinical staging guidelines and/or pathologic staging guidelines.

Restaging is used to determine the extent of the disease if a cancer comes back after treatment. Restaging helps determine the and the best treatment options for cancer that has returned.

What are the Common Elements of Staging Systems?

Staging is based on commonly understood knowledge about the way cancer develops and spreads.

In most cases, the stage is based on four main factors:

Location of the primary (original) tumor

Tumor size and extent of tumors

Lymph node involvement (whether or not the cancer has spread to the nearby lymph nodes)

Presence or absence of distant metastasis (whether or not the cancer has spread to distant areas of the body)

How does Staging Work?

Doctors collect data about a cancer to determine its stage. This information comes from the various tests used to identify staging in different types of cancer.

These tests can include:

Physical examinations that can provide clues as to the extent of the cancer. The physical exam may determine the location and size of the tumor(s) and provide additional information on whether the cancer has spread to the lymph nodes and/or to other organs.

Imaging tests such as x-rays, CT scans, and MRI scans can show the location of the cancer, the size of the tumor, and whether the cancer has spread.

Laboratory tests that provide information on blood, urine and other fluids and tissues removed from the body.

Pathology reports that can provide information about the size of the tumor, the growth into other tissues and organs, the type of cancer cells and the grade of tumor (how closely the cancer cells resemble normal tissue). Pathology reports often confirm the diagnosis of cancer, as well as the stage.

Surgical reports from samples removed during surgery can determine the size and appearance of a tumor and provide insights about lymph node and organ involvement.

What is the TNM Staging System?

​The TNM Staging System was developed and is maintained by the AJCC and the Union for International Cancer Control (UICC). It is the most commonly used staging system by medical professionals around the world. The TNM classification system was developed as a tool for doctors to stage different types of cancer based on certain, standardized criteria.

The TNM Staging System is based on the extent of the tumor (T), the extent of spread to the lymph nodes (N), and the presence of metastasis (M).

The T category describes the original (primary) tumor.

TX​

Primary tumor cannot be evaluated​

T0

No evidence of primary tumor​

Tis​

Carcinoma in situ (early cancer that has not spread to neighboring tissue)​

T1–T4​

Size and/or extent of the primary tumor​

The N category describes whether or not the cancer has reached nearby lymph nodes

NX

Regional lymph nodes cannot be evaluated​

N0

No regional lymph node involvement (no cancer found in the lymph nodes)

N1-N3​

Involvement of regional lymph nodes (number and/or extent of spread)

The M category tells whether there are distant metastases (spread of cancer to other parts of the body).

M0

No distant metastasis (cancer has not spread to other parts of the body)​

M1

Distant metastasis (cancer has spread to distant parts of the body)

Because each cancer type has its own classification system, letters and numbers do not always mean the same thing for every kind of cancer. Once the T, N, and M are determined, they are combined, and an overall stage of 0, I, II, III, IV is assigned. Sometimes these stages are subdivided as well, using letters such as IIIA and IIIB.

In some cancer types, non-anatomic factors are required for assigning the anatomic stage/prognostic group. These are clearly defined in each chapter of the AJCC Cancer Staging Manual (e.g. Gleason Score in Prostate). These factors are collected separately from T, N, and M, which remain purely anatomic and are used to assign stage groups.

Where non-anatomic factors are used in groupings, there is a definition of the groupings provided for cases where the non-anatomic factor is not available (X) or where it is desired to assign a group ignoring the non-anatomic factor.

Stage I cancers are the least advanced and often have a better prognosis. Higher stage cancers are often more advanced but in many cases can still be treated successfully.

Does the Stage of a Cancer Change?

The formal stage of a cancer does not change over time, even if the cancer progresses. A cancer that returns or spreads is still referred to by the stage it was given when it first diagnosed. In certain cases, after a period of remission a doctor might restage the cancer, but this does not happen very often. If the cancer is restaged, the same process that was done when the cancer was first diagnosed will be repeated: exams, imaging tests, biopsies, and possibly surgery. The new stage will be recorded with a lower case "r" before the restaged designation.